Background Body habitus, pneumoperitoneum, and Trendelenburg positioning may each independently impair lung mechanics during robotic laparoscopic surgery. This study hypothesized that increasing body mass index is associated with more mechanical strain and alveolar collapse, and these impairments are exacerbated by pneumoperitoneum and Trendelenburg positioning. Methods This cross-sectional study measured respiratory flow, airway pressures, and esophageal pressures in 91 subjects with body mass index ranging from 18.3 to 60.6 kg/m2. Pulmonary mechanics were quantified at four stages: (1) supine and level after intubation, (2) with pneumoperitoneum, (3) in Trendelenburg docked with the surgical robot, and (4) level without pneumoperitoneum. Subjects were stratified into five body mass index categories (less than 25, 25 to 29.9, 30 to 34.9, 35 to 39.9, and 40 or higher), and respiratory mechanics were compared over surgical stages using generalized estimating equations. The optimal positive end-expiratory pressure settings needed to achieve positive end-expiratory transpulmonary pressures were calculated. Results At baseline, transpulmonary driving pressures increased in each body mass index category (1.9 ± 0.5 cm H2O; mean difference ± SD; P < 0.006), and subjects with a body mass index of 40 or higher had decreased mean end-expiratory transpulmonary pressures compared with those with body mass index of less than 25 (–7.5 ± 6.3 vs. –1.3 ± 3.4 cm H2O; P < 0.001). Pneumoperitoneum and Trendelenburg each further elevated transpulmonary driving pressures (2.8 ± 0.7 and 4.7 ± 1.0 cm H2O, respectively; P < 0.001) and depressed end-expiratory transpulmonary pressures (–3.4 ± 1.3 and –4.5 ± 1.5 cm H2O, respectively; P < 0.001) compared with baseline. Optimal positive end-expiratory pressure was greater than set positive end-expiratory pressure in 79% of subjects at baseline, 88% with pneumoperitoneum, 95% in Trendelenburg, and ranged from 0 to 36.6 cm H2O depending on body mass index and surgical stage. Conclusions Increasing body mass index induces significant alterations in lung mechanics during robotic laparoscopic surgery, but there is a wide range in the degree of impairment. Positive end-expiratory pressure settings may need individualization based on body mass index and surgical conditions. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Background Hypotension and bradycardia are known side effects of spinal anesthesia in pregnant women undergoing cesarean section and adults undergoing other surgical procedures. Whether children experience similar hemodynamic changes is unclear. Aims The purpose of this study is to evaluate hemodynamic effects of spinal anesthesia compared to general anesthesia in a cohort of healthy infants. Methods The University of Vermont Medical Center almost exclusively used spinal anesthesia for infant pyloromyotomy surgery between 2008–2013, while Columbia University Medical Center relied on general anesthesia. The primary outcome assessed was the percentage change in intraoperative heart rate and blood pressure (systolic [SBP] and mean [MAP] blood pressure) from baseline. Analysis was performed using t-tests for continuous variables, followed by linear regression to account for differences in demographic and clinical covariates. Results The study sample consisted of 51 infants with spinal anesthesia at the University of Vermont and 52 infants with general anesthesia at Columbia University. The decrease from baseline for mean intraoperative SBP was −8.2 ± 16.8% for SA and −24.2 ± 17.2% for GA (difference between means: 16.2% [95% confidence interval (CI), 9.5–22.9]), while the decrease from baseline for mean intraoperative MAP was −16.3 ± 19.9% for SA and −24.6 ± 19.3% for GA (difference between means: 8.4% [95% CI, 0.8–16]). SA patients also had smaller drops in minimum intraoperative MAP and SBP. These blood pressure differences persisted even after adjusting for covariates. No differences in heart rate were seen between spinal and general anesthesia. Discussion Our findings show that spinal anesthesia performed in healthy infants undergoing pyloromyotomy results in reduced intraoperative blood pressure changes from baseline, significantly higher blood pressure readings, and no increased bradycardia compared to general anesthesia. Further research is needed to assess whether any clinical impact of these hemodynamic differences between spinal and general anesthesia exists.

Background and Objectives Interest in spinal anesthesia (SA) is increasing due to concern about the long-term effects of intravenous and inhaled anesthetics in young children. This study compared SA versus general anesthesia (GA) in infants undergoing pyloromyotomy. Methods Between 2000 to 2013, the University of Vermont Medical Center (UVMMC) almost exclusively used SA for infant pyloromyotomy surgery, while Columbia University Medical Center (CUMC) relied on GA. Outcomes included adverse events (AE) within 48 hours of surgery, operating room (OR) time, and postoperative length of stay (LOS). Regression was used to evaluate the association between anesthesia technique and outcomes, accounting for demographic and clinical covariates. Results We studied 218 infants with SA at UVMMC and 206 infants with GA at CUMC. In the SA group, 96.3% of infants had adequate initial analgesic levels but 35.8% required supplemental IV or inhaled anesthetic agents. Compared with GA, the risk of AEs in SA (adjusted odds ratio [aOR], 0.60; 95% CI, 0.27 – 1.36) did not differ, but SA was associated with shorter OR times (17.5 minutes faster; 95% CI, 13.5 – 21.4 minutes) and shorter postoperative LOS (GA is 1.19 times longer; 95% CI, 1.01 – 1.40). Discussion Infants undergoing pyloromyotomy with SA had shorter OR times and postoperative LOS, no differences in AE rates, and decreased exposure to intravenous and inhaled anesthetics, although SA infants often still required supplemental anesthetics. Whether these differences result in any long-term benefit is unclear; further studies are needed to determine the risk of rare AEs, such as aspiration.

We found no link between duration of surgery with infant SA and scores on academic achievement testing in elementary school. We also found no relationship between infant SA and surgery with VPAA on elementary school testing, although the CIs were wide.

In comparison to systemic administration, there is no selective benefit to adding ketamine to the IVRA injectate.